ssh-agent error "Could not open a connection to your authentication agent." [duplicate]

Question

Did You Start ssh-agent?

You might need to start ssh-agent before you run the ssh-add command:

eval `ssh-agent -s`
ssh-add

Note that this will start the agent for msysgit Bash on Windows. If you're using a different shell or operating system, you might need to use a variant of the command, such as those listed in the other answers.

See the following answers:

1. ssh-add complains: Could not open a connection to your authentication agent
2. Git push requires username and password (contains detailed instructions on how to use ssh-agent)
3. How to run (git/ssh) authentication agent?.
4. Could not open a connection to your authentication agent

To automatically start ssh-agent and allow a single instance to work in multiple console windows, see Start ssh-agent on login.

Why do we need to use eval instead of just ssh-agent?

To find out why, see Robin Green's answer.

Public vs Private Keys

Also, whenever I use ssh-add, I always add private keys to it. The file ~/.ssh/id_rsa.pub looks like a public key, I'm not sure if that will work. Do you have a ~/.ssh/id_rsa file? If you open it in a text editor, does it say it's a private key?

I tried the other solutions to no avail. I made more research and found that the following command worked. I am using Windows 7 and Git Bash.

eval $(ssh-agent)

More information in: https://coderwall.com/p/rdi_wq

The following command worked for me. I am using CentOS.

exec ssh-agent bash

Could not open a connection to your authentication agent

To resolve this error:

bash:

$ eval `ssh-agent -s`

tcsh:

$ eval `ssh-agent -c`

Then use ssh-add as you normally would.

---

Hot Tip:

I was always forgetting what to type for the above ssh-agent commands, so I created an alias in my .bashrc file like this:

alias ssh-agent-cyg='eval `ssh-agent -s`'

Now instead of using ssh-agent, I can use ssh-agent-cyg

E.g.

$ ssh-agent-cyg
SSH_AUTH_SOCK=/tmp/ssh-n16KsxjuTMiM/agent.32394; export SSH_AUTH_SOCK;
SSH_AGENT_PID=32395; export SSH_AGENT_PID;
echo Agent pid 32395;
$ ssh-add ~/.ssh/my_pk

---

Original Source of fix:

http://cygwin.com/ml/cygwin/2011-10/msg00313.html

MsysGit or Cygwin

If you're using Msysgit or Cygwin you can find a good tutorial at SSH-Agent in msysgit and cygwin and bash:

1. Add a file called .bashrc to your home folder.

2. Open the file and paste in:

   #!/bin/bash
   eval `ssh-agent -s`
   ssh-add
   

3. This assumes that your key is in the conventional ~/.ssh/id_rsa location. If it isn't, include a full path after the ssh-add command.

4. Add to or create file ~/.ssh/config with the contents

   ForwardAgent yes
   

   In the original tutorial the ForwardAgent param is Yes, but it's a typo. Use all lowercase or you'll get errors.

5. Restart Msysgit. It will ask you to enter your passphrase once, and that's it (until you end the session, or your ssh-agent is killed.)

Mac/OS X

If you don't want to start a new ssh-agent every time you open a terminal, check out Keychain. I'm on a Mac now, so I used the tutorial ssh-agent with zsh & keychain on Mac OS X to set it up, but I'm sure a Google search will have plenty of info for Windows.

Update: A better solution on Mac is to add your key to the Mac OS Keychain:

ssh-add -K ~/.ssh/id_rsa

Simple as that.

Run

ssh-agent bash
ssh-add

To get more details you can search

ssh-agent

or run

man ssh-agent